Cleaning up the wiring harness

[bradrs]

So shrinking Raychem over 25 year old wiring is doing it right? /ubbthreads/images/graemlins/dunno.gif

Be careful around the connectors, and leave a little room between the Raychem and the connector, and try not to make the bends too tight just past the connector. Several of the installs in that Honda thread had the wire bent sharp right past the connector. You want to have bigger loops there.

You were asking for a depin tool. Pico 0660PT is a set from Summit for $7. Aside from that, some jewelers screwdrivers can help too.

I'd really suggest rethinking that and using the split loom to just repair the covering, I'd put money on damaging some wire, terminals, and/or connectors while doing the Raychem.

And while someone DOES have many/most of the connectors available new, it seems kinda silly to do all that for just a new wire cover on an old harness.

 

[GSTwithPSI]

25 years old or not, my harness wiring is in good shape. I'll assume that's because the shitty split loom and electrical tape did its job for the most part. It's the split loom and electrical tape that's trashed, not the wiring. I'm not sure what's giving you the impression the wiring on my (or others' cars) is messed up. It's not.

If I wanted to settle on split loom and electrical tape, I would have just left it be. The whole point of redoing the sheathing with the Raychem was to improve the overall look, while adding some extra protection to the wiring. Even cheap shrink tube from the hardware store would be better than electrical tape and ribbed split loom, which is what it came with from the factory.

I have a spare harness I cannibalize for connectors and such. If I screw one up removing it, i'll just replace it. I'll make sure to have proper loops and ensure there aren't any kinks in the harness, thanks for the tip. When all the stuff gets here, I'll post some pictures of the process.

 

[bradrs]

The wire loom doesn't protect the wire from heat cycles, it only provides some mechanical protection. But that same loom also can damage the wires.

Corrosion that appear to start at exposed connectors(and there are quite a few unsealed connectors underhood) will work their way up the wires. Underhood chemicals will affect the wire sheathings over time. Vibration will have it's way with the in harness splices. Over time the wire and sheathing will lose flexibility.

What surprises me is you see the evidence of what 25 years underhood has done to the loom, and you don't think it had any adverse affects on the wires.

 

[pot]

I began cleaning up the wiring harness on 182 about a year and a half ago. Prior to that, when I installed my AMS SMIM the harness left an eyesore with respect to the Injectors, Coil pack, Ignitor, and Throttle Cable. I began by rerouting the injector portion of the harness and breaking it up individually by separating the: TPS, CAS, Coil Pack, and Ignitor.

For reference there are 3 main separate portions of the harness:

- Engine Management Portion (ECU)
- Chassis Portion
- Interior

I focused my efforts on the ECU portion of the wiring harness with an emphasis on removing emission components and removing as many items from the firewall while ensuring I can still pass NC emissions. For reference I've included some images, This is how I started:



This little bugger behind the glove box needs to be removed in order to pull the harness in either direction through the firewall. Its held in place by a 10mm nut:



While it isn't necessary to remove the harness from the interior side if your only rerouting some of the items I mentioned earlier, but if you want to remove emissions and cruise control this is the way to go. Below are some of the components I removed:

Cruise Control Actuator



EGR Control Solenoid



Fuel Pressure Solenoid



Fuel Pressure Control Solenoid Valve



Brake Fluid Level Sensor



*I did remove 2 of the 3 grounds from the harness that are located on the firewall and found a spot for it lower on the firewall away from view along with the resistor pack. In addition, I relocated the Wiper Relay, Engine Timing Pin, and Fuel Pump Check Plug into the interior.

At 22 years old, I found 98% of my harness in like new condition. The trouble spots were around the water neck i.e. Coolant Temperature Sensor, A/C Coolant Temp Switch, the Coolant Temp Gauge Unit, and the other A/C plug.

There has been lots of good info on here regarding this process and required tools and materials. I agree with what some members have said with regard to taping the harness prior to placing it into the loom. I use 3M Super 33 as it thick enough to protect the wiring but doesn't leave sticky residue while remaining pliable. I do not recommend 3M Super 88 (having used it already) as it leaves more of a mess than when you first broke into the harness.

Below is a picture of the terminal pick set that I used throughout this process. I only bought this set about 3 - 4 years ago as it was on sale. My recommendation is to buy a good high quality set by OTC from Amazon. Same stuff, but better and cheaper. Be cognizant though, these tools have a tendency to snap, its not uncommon.



There's much more I probably left out but feel free to hit me up with any questions you may have. I found this to be one of the more enjoyable projects thus far. In the longterm, my plan is to:

- Completely relocate the entry point for the ECU portion of the harness to near where the shift cables enter the firewall
- Weld/bondo shut the original hole where harness enters now
- Relocate the fuse box behind the glove box

 

[strokin4dr]

Good luck with the project. I'm looking forward to the results. I know first hand how much work is involved in such a project.

I also stripped all ABS, auto seatbelt, etc wiring from the chassis harness. Easily over 10 lbs of wire removed /ubbthreads/images/graemlins/rofl.gif

 

[pot]

I referenced you earlier in this thread Ryan. You were the one through your post about 3 - 4 years ago that inspired me to tackle on this job. While not nearly anywhere close to what you did with your harness I'd like to someday tackle this on 182.

 

[bradrs]

Quoting pot:

At 22 years old, I found 98% of my harness in like new condition. The trouble spots were around the water neck i.e. Coolant Temperature Sensor, A/C Coolant Temp Switch, the Coolant Temp Gauge Unit, and the other A/C plug.

There has been lots of good info on here regarding this process and required tools and materials. I agree with what some members have said with regard to taping the harness prior to placing it into the loom. I use 3M Super 33 as it thick enough to protect the wiring but doesn't leave sticky residue while remaining pliable. I do not recommend 3M Super 88 (having used it already) as it leaves more of a mess than when you first broke into the harness.




That end result looks good. Has your car spent all of its life in NC? I've seen vehicles that are only a few years old where the harnesses looked like they were in much worse shape. But they are vehicles that are driven on salted roads etc.

Taping inside helps, but the tape suggestions I had on that were to use an antiabrasion tape that is more like a very slick fabric tape. That keeps the conduit from biting in and cutting it . Then if you tape OUTSIDE of the conduit the full length, you can seal the conduit so water doesn't get in. Some OEMs do this on low hanging conduit. Otherwise, your conduit can collect water, mud etc and hold it there to damage the harness.

 

[GSTwithPSI]

Quoting bradrs:
What surprises me is you see the evidence of what 25 years underhood has done to the loom, and you don't think it had any adverse affects on the wires.



I don't think that. I can only speak for the condition of my harness specifically. I've seen plenty of places where the harness needed attention, and I've addressed them. Overall though, just as Pot said, ~98% of my harness is in great shape. In regard to the condition of the loom; if you have an example of 25 year old tape that doesn't look like sh*t, I'd love to see it. Expose tape and split loom to 25 years of wear and tear (even under modest conditions) and it will start to fall apart and look like sh*t in places. I guarantee it.


Quoting bradrs:
The wire loom doesn't protect the wire from heat cycles, it only provides some mechanical protection. But that same loom also can damage the wires.

Corrosion that appear to start at exposed connectors(and there are quite a few unsealed connectors underhood) will work their way up the wires. Underhood chemicals will affect the wire sheathings over time. Vibration will have it's way with the in harness splices. Over time the wire and sheathing will lose flexibility.



I'm assuming when you mention heat cycles, you mean radiant heat from the loom being exposed to under hood conditions (such as from other engine components), not actually heat caused by current moving through the wire.

If we are on the same page about radiant heat, the Raychem DR-25 does provide a heat barrier, and it is also chemical resistant. It's not bulletproof, but it provides far more protection than tape and ribbed split loom ever could. OEMs use tape and split loom because it's cheap, and works well for what it is.

I'm not sure how many DSM-like harness you've had you hands on, but every one I've ever touched suffers from the same issues. Some of the more common problems/areas are:

- Connectors/wiring around the T-stat housing turn crispy and brittle
- Anywhere the loom bends, the tape and covering deteriorates
- Old style injector clips are almost always broken/loose/missing
- CAS and TPS wiring has no harness relief, so the wires get brittle and broken
- Alternator wiring usually is trashed due to common oil leaks in that area
- S terminal on the starter is usually corroded
- FPS BCS connectors are usually corroded because they get unplugged and left hanging

Below are some pictures from my car, although every DSM-like harness I've ever touched looked identical...

Here are a few pieces of ribbed split loom that actually looked pretty good. They are pretty brittle, but still functional overall:

Here's some split loom and tape that doesn't look so good:

Here's a piece of split loom that is in sad ass shape. Notice the large hole. The hole is exactly where this piece of loom was bent at about 45 degrees. As the loom is forced to bend, it puts pressure on the plastic. Over time, that pressure causes the loom to deteriorate, and fall apart (as seem in this photo). This wasn't caused by salt, dirt, or misuse. This is caused by age and time, and happens to almost all split loom I've ever seen on older vehicles:

Here's a good example of what happens to plastic split loom and electrical tape when exposed to oil for long periods of time. The loom and tape get brittle, eventually deteriorating and falling apart. In this state, the tape is no longer flexible, and also no longer provides any protection from moisture or dirt. Of note, this piece of loom looked clean from the outside before I removed it. I had addressed the oil leak (from before I owned the car) in this area or the loom, and cleaned the harness. I cleaned the engine bay and entire wiring harness last time I had the motor out of the car (less than 8 months ago). However, oil had already collected between the tape and loom prior to this, which trashed it. So, even after repairing the oil leak and cleaning the harness, the loom still retained residual oil, causing it to further deteriorate:

So what does the wiring look like under that crusty piece of loom? Well, just fine, actually:

A few shots of the rest of the harness:

Good connector:

BAD connector:

In summary, I believe the Raychem covering will be a great improvement over tape and split loom. That's just my honest opinion.

 

[bradrs]

In response to the guy asking about the wires, I was trying to get them to match many of the colors on the 90 Eclipse I am helping to rewire. I definitely don't have them all yet, but I am working on it. The annoying thing about it is they changed the wire colors from year to year. Drop me a line with specific colors and gauges you want, and I will see what I have.

 

[bradrs]

Quoting GSTwithPSI:


I don't think that. I can only speak for the condition of my harness specifically. I've seen plenty of places where the harness needed attention, and I've addressed them. Overall though, just as Pot said, ~98% of my harness is in great shape. In regard to the condition of the loom; if you have an example of 25 year old tape that doesn't look like sh*t, I'd love to see it. Expose tape and split loom to 25 years of wear and tear (even under modest conditions) and it will start to fall apart and look like sh*t in places. I guarantee it.




That was my point, you are having to cut/splice/otherwise repair your harness to fix SERIOUS problems. Like the toasted wires you mention, corroded terminals, etc. My point is that those problems don't just happen suddenly one day. Many of the other wires will have the same abuse, just to a lesser degree. But now you have a wire loom with lots of old wire and connectors, some new wire spliced in, and wrapped pretty.

Quoting GSTwithPSI:
I'm assuming when you mention heat cycles, you mean radiant heat from the loom being exposed to under hood conditions (such as from other engine components), not actually heat caused by current moving through the wire.

If we are on the same page about radiant heat, the Raychem DR-25 does provide a heat barrier, and it is also chemical resistant. It's not bulletproof, but it provides far more protection than tape and ribbed split loom ever could. OEMs use tape and split loom because it's cheap, and works well for what it is.




Yes, radiant heat. Where have you read that the DR-25 provides a better heat barrier? The way the loom is, it basically is a thin layer of the material, plus an air gap. If you are familiar at all with thermal conductivity, air is one of the worst conductors of heat, several orders of magnitude more insulative than any of the other materials in the harness. I see that all the time in electronics design. Anyhow, by heatshrinking the DR-25, you lose that gap, and you are also bundling all the wires together tighter. Which is good mechanically, but bad from a heat standpoint.


Quoting GSTwithPSI:

I'm not sure how many DSM-like harness you've had you hands on, but every one I've ever touched suffers from the same issues. Some of the more common problems/areas are:

- Connectors/wiring around the T-stat housing turn crispy and brittle
- Anywhere the loom bends, the tape and covering deteriorates
- Old style injector clips are almost always broken/loose/missing
- CAS and TPS wiring has no harness relief, so the wires get brittle and broken
- Alternator wiring usually is trashed due to common oil leaks in that area
- S terminal on the starter is usually corroded
- FPS BCS connectors are usually corroded because they get unplugged and left hanging




That sounds like a lot more than 2% by itself. I know most of those problems based on the number of requests I get for those parts.

Quoting GSTwithPSI:

In summary, I believe the Raychem covering will be a great improvement over tape and split loom. That's just my honest opinion.



And my honest opinion is that putting Raychem over 25 year old wiring is like chroming a turd /ubbthreads/images/graemlins/smile.gif The turd will definitely lose some strength in the process of prettying it up.

Your good connector image looks like the wire may not be as flexible now as new wire should be, like it is stuck in the position of the original loom. Your description of wires soaked in oil for a long time sounds like some abuse that isn't good for the wires too. You are going to be pulling hard on some of these stiff wires to depin, potentially making things worse. And the areas where the wire was bent around tight corners etc, you are probably going to be straightening that old wire then bending it again..

Raychem makes sense on a new harness where you can spend a lot of time electrically checking EVERYTHING before the DR-25 is sealed up. On an older harness, I'd rather have something a little easier to open up if there is a problem.

 

[GSTwithPSI]

Quoting bradrs:
That was my point, you are having to cut/splice/otherwise repair your harness to fix SERIOUS problems. Like the toasted wires you mention, corroded terminals, etc. My point is that those problems don't just happen suddenly one day. Many of the other wires will have the same abuse, just to a lesser degree. But now you have a wire loom with lots of old wire and connectors, some new wire spliced in, and wrapped pretty.




If you've ever owned a car that's 25 years old, you've repaired the harness a time or two. I've done it hundreds of times, and so have others. All my repairs are done with solder and sealed with shrink tube. If you run a completely new wire from end to end every time you need to make a repair, you're one of the few.

Quoting bradrs:
Yes, radiant heat. Where have you read that the DR-25 provides a better heat barrier? The way the loom is, it basically is a thin layer of the material, plus an air gap. If you are familiar at all with thermal conductivity, air is one of the worst conductors of heat, several orders of magnitude more insulative than any of the other materials in the harness. I see that all the time in electronics design. Anyhow, by heatshrinking the DR-25, you lose that gap, and you are also bundling all the wires together tighter. Which is good mechanically, but bad from a heat standpoint.


According to the Raychem tech sheet:
Specially formulated for
optimum high temperature
fluid resistance, and long
term heat resistance.
Resistant to aviation and
diesel fuels, hydraulic fluids
and lubricating oils. ---> click

Whether the wires are taped together and then stuffed in split loom, or heatshrinked together, I doubt there's a measurable real world difference. Not to mention, I'll be separating parts of the harness that were previously bunched together. We are talking about a piece of copper wire here, not a microprocessor.

Quoting bradrs:
That sounds like a lot more than 2% by itself. I know most of those problems based on the number of requests I get for those parts.


I think you misunderstood what I was saying. I was describing the issues I've seen in general. These aren't exclusive to my current car.

Quoting bradrs:
And my honest opinion is that putting Raychem over 25 year old wiring is like chroming a turd The turd will definitely lose some strength in the process of prettying it up.

Your good connector image looks like the wire may not be as flexible now as new wire should be, like it is stuck in the position of the original loom. Your description of wires soaked in oil for a long time sounds like some abuse that isn't good for the wires too. You are going to be pulling hard on some of these stiff wires to depin, potentially making things worse. And the areas where the wire was bent around tight corners etc, you are probably going to be straightening that old wire then bending it again..

Raychem makes sense on a new harness where you can spend a lot of time electrically checking EVERYTHING before the DR-25 is sealed up. On an older harness, I'd rather have something a little easier to open up if there is a problem.


Aside from building a completely new harness, there's not way to avoid the things you mentioned above. I don't think you're being realistic about how durable the harness is, even after years or wear and tear. Other than being easier to open up, personally, I just don't see any real advantage to using tape and split loom. Hence, my choice to go with the Raychem stuff.

 

[bradrs]

Quoting GSTwithPSI:

If you've ever owned a car that's 25 years old, you've repaired the harness a time or two. I've done it hundreds of times, and so have others. All my repairs are done with solder and sealed with shrink tube. If you run a completely new wire from end to end every time you need to make a repair, you're one of the few.




I'd just repair ONLY the section that needed to be repair. Completely disassembling the harness, depinning, etc, just to replace a single bad wire would make about as much sense to me as completely disassembling an old harness to replace the covering with a heatshrink.


Quoting GSTwithPSI:

According to the Raychem tech sheet:
Specially formulated for
optimum high temperature
fluid resistance, and long
term heat resistance.




That means the material won't melt, it says nothing about how it transfers heat. Feel free to contact them to get the thermal conductivity, but it won't be good or outside the normal for similar materials, or otherwise they'd mention it on the datasheet. Have you ever looked at tables of thermal conductivity of various materials? It will confirm what I said about the heat transfer of air, vs. typical materials similar to the DR-25 material.

Quoting GSTwithPSI:

Whether the wires are taped together and then stuffed in split loom, or heatshrinked together, I doubt there's a measurable real world difference. Not to mention, I'll be separating parts of the harness that were previously bunched together. We are talking about a piece of copper wire here, not a microprocessor.



Actually, my experience is with engine bay mounted control modules, ignition power transistors, etc. They run several amps through copper traces on PCBs, in and out of wiring harnesses attached to the module. motionless air is a great insulator. Your DR-25 probably doesn't compare, it will pass the engine bay heat through much easier. So I wouldn't list that as one of the reasons/advantages of putting it on.




Quoting GSTwithPSI:

Aside from building a completely new harness, there's not way to avoid the things you mentioned above. I don't think you're being realistic about how durable the harness is, even after years or wear and tear. Other than being easier to open up, personally, I just don't see any real advantage to using tape and split loom. Hence, my choice to go with the Raychem stuff.



Tape and split loom would be considerably easier. No depinning, you could probably even leave the harness in place for the most part. I don't see the advantage to DR-25, aside from the mad props you will get from the Honda crowd(and G). The split loom lasted 25 years. If you do a better job taping and split looming, it might last that long again. Probably much longer than the rest of the harness/repairs. Putting DR-25 on it isn't going to make it last longer. Aside from the extra time on jackstands extending it's life a little

 

[GSTwithPSI]

Well, I guess we'll have to agree to disagree.

I'm not going to call the manufacturer to research the thermo conductivity of some shrink tubing just so I can throw it on a piece of ~18 gauge wire. That sentence actually sounds pretty ridiculous as I write it. The little tech sheet that I linked to, coupled with some real world applications I've seen DR-25 used in are enough to convince me it's good stuff. If you're convinced some electrical tape works better, cool. Either method would get the job done honestly, so it all boils down the the time and effort you're willing to put in, as well the end result you'd like to achieve. If I fit in with the Honda boyz after this is all said and done, I'm fine with that.

We aren't building the space shuttle here, just depinning a connector and putting some new covering on an old piece of wire. As technically advanced and horrible as you make that sound, it's really not.

 

[bradrs]

I wouldn't say that we are agreeing to disagree. I am stating facts based on readily researchable science, and you are too lazy to look it up or get facts.Instead you'd rather believe that DR-25 somehow is a magic insulator. It has to be good, all the honda boys love it!

click

There you go. Air is better than anything but some other gases.

The motorsports harnesses using raychem are using wire with a much higher temp rated wire that what many people use. That is why their harnesses take the heat, not any magical properties of DR-25.

I don't know what the exact wire spec is on the wire used on these cars, but the common JDM wire specs are only good to 80C. So the raychem will stay good as the wires melt together inside. There is your weak point if you are really concerned about the heat. The newer US spec wire is rated to 125C. If you wanted to make a new harness with 125C rated wire, or the higher rated stuff used in motorsports, then it'd make sense to want a covering that is rated to that high a temp.

You are right, it isn't rocket science to pull the harness apart and replace the split wall with dr-25. I am just pointing out that most of your reasons for doing it aren't valid. So the only real reason to do it is for the mad props you will get. Good luck with it though.

 

[GSTwithPSI]

You are seriously overcomplicating a very simple issue, IMO. How much AIR do you think gets trapped in a bunch of wires that get bundled up and taped/heatshrinked together? It's pretty simple; you take a bunch of wires, bundle them up and either tape or shrink them together. The two mediums we're discussing here that would be responsible for holding that wire bundle together are 1) tape or 2) Raychem DR-25. From everything I can see, the DR-25 looks like medium with the most benefits to offer. Feel free to point out the scientific data showing how electrical tape would do a better job trapping air in a bunch of wires. More importantly, lets consider how much that really f***ing matters in the first place. If you route the wires properly keeping them away from major heat sources, you just solved half of the problem. Seems to me you spend lots of time in the theoretical world, and not too much time under the hood actually getting your hands dirty. I'm looking forward to posting the results of this project, and putting some of your fears to rest.

I'm still confused on what your point is exactly? Are you saying I'd be better off taping up the harness than using the DR-25? Or are you just upset that I'm taking the time to do something you deem a waste of time?

 

[bradrs]

And you are seriously underthinking something that should be extremely obvious. The DR-25 isn't going to provide any heat protection. That is why I pointed out the wiring REAL motorsports looms are made with. It isn't 25 year old AVSS that is rated at a max temp of 80C.

Look at the loom. Do you see the corrugated part of it? That is the trapped pockets of air that will insulate the wires. If you think those pockets aren't big, they aren't. But they are signficantly thicker than the DR-25. So you can choose between a thicker layer of a poor conductor of heat(air), or a thinner layer of a better conductor of heat(DR-25). So it should be ridiculously obvious that the DR-25 won't do anything for you temp wise, except possibly allow your wires to get hotter. But hey, they are still working after 25 years, so no need to think any changes through, right?


Quote:

I'm still confused on what your point is exactly? Are you saying I'd be better off taping up the harness than using the DR-25? Or are you just upset that I'm taking the time to do something you deem a waste of time?



You'd be better off using the fabric split loom and tape on the harness. I'm not upset, just pointing out that you aren't going to get the benefits you hope. I will still happily give you little pointers like I did earlier, to help with assembly.

The only real benefit of the DR-25 I could see would be in case of an engine fire. Your low temp rated wires will probably still cook inside it, but the DR-25 should keep the mess contained and easier to remove. That old loom is probably rated to around the same temp as the wires.

 

[GSTwithPSI]

I think there's a bit of a disconnect here.

I'm not ditching all the split loom in favor of DR-25. I'm starting with my 25 year old bare wire. I'm removing the old shitty tape, and replacing it with DR-25. In addition, I'll replace the split loom where needed. When it's all said in done, the harness will essentially be the same. The only difference will be it will no longer have tape under the loom (it will be covered in DR-25 instead), and it will be split up and routed according to component location. If that's not an improvement over stock, I don't know what is. There will be plenty of places where the harness not covered by split loom, just as there are from the factory. Those places will still be covered in DR-25, and routed away from major heat sources.

If what I've described above still seems poorly conceived to you, I'm not sure what to say.

 

[89Patches]

Wow.

You two have made this in to rocket science. Guess what? If your car catches on fire nothing is going to save your wiring...

 

[bradrs]

Quoting GSTwithPSI:
I think there's a bit of a disconnect here.

I'm not ditching all the split loom in favor of DR-25. I'm starting with my 25 year old bare wire. I'm removing the old shitty tape, and replacing it with DR-25. In addition, I'll replace the split loom where needed. When it's all said in done, the harness will essentially be the same. The only difference will be it will no longer have tape under the loom (it will be covered in DR-25 instead), and it will be split up and routed according to component location. If that's not an improvement over stock, I don't know what is. There will be plenty of places where the harness not covered by split loom, just as there are from the factory. Those places will still be covered in DR-25, and routed away from major heat sources.

If what I've described above still seems poorly conceived to you, I'm not sure what to say.



When you started comparing DR-25 to split loom+tape, it sounded like you wanted to use the DR-25 in place of both of them. And the first few pics from the Honda thread show that as well. So it seemed like you wanted to just use the raychem.

Using both will definitely be a lot of protection on the wire. Either one really should be adequate by itself. I'd go the simpler route and do some sort of split jacket, but everyone has preferences.

One thing to consider is that the DR-25 is the part that is more resistant to oils etc. And it is abrasion resistant. Just wrapping it with anti abrasion tape MIGHT be enough, without having to add conduit also.

The other thing to consider is that if you are adding both of those layers of protection, you are adding a lot of additional weight. Which can lead to lots of harness problems on its own. Make sure to add more mounting brackets etc to hold the harness and keep it from moving around. Otherwise, you will start breaking wires at the connector from the weight of the harness.

 

[GSTwithPSI]

What's this anti-abrasion tape you keep mentioning? Is there a specific type or brand you'd recommend?